Standard frontal view (PA/Posterior-Anterior): The x-ray beam
travels six feet posterior to anterior through the upright (standing) patient
in a horizontal plane. This distance is ideal to reduce magnification
and enhance image sharpness. The hemidiaphragms are lower on the upright
film, allowing you to see more of the lung. However, very sick patients are
often unable to sit upright or stand. In these cases, an AP (anterior-posterior)
view is taken with the x-ray beams traveling vertically to a film 48 inches
from the patient. Note that when an AP film is taken, structures (like
the heart) may be magnified and borders may be less sharp.

Lateral view: This view may expose lesions
that are retrosternal or hidden by the diaphragm. The patient is placed with
the film against the side of the chest where the lesion is suspected. For example,
a left lateral view (with the left side of the chest held against the film)
would be used to examine the area behind the left side of the heart. It
is best when the lesion is as close to the film as possible.

Decubitus view (Cross-table Lateral): The
patient is in the supine position with the x-ray beams traveling horizontally
and parallel to the floor. This view takes advantage of gravity. If free fluid
is suspected in the lung, this view forces fluid toward the patient’s
back. In a conventional left lateral decubitus film, the patient is lying on
one side and fluid is forced to the lateral thorax. Either view is ideal for
identification of air-fluid levels in the lung.